Celtic's 6-1 demolition by Barcelona brought to an end an utterly miserable Champions League campaign which saw the Scottish champions end bottom of their group with the second-worst goal difference in the group stages, after Anderlecht.

Celtic's 6-1 demolition by Barcelona brought to an end an utterly miserable Champions League campaign which saw the Scottish champions end bottom of their group with the second-worst goal difference in the group stages, after Anderlecht.

There has been some speculation about why Celtic looked so far off the pace after last year's heroic progress to the last 16 which included that famous victory over Barcelona at Parkhead. The problem is that it's last year which was the aberration, this year's performance is perfectly in keeping the club's other recent European campaigns.

In 2011, they were knocked out of the Europa League at the play-off stage by Sion before being reinstated when the Swiss side were chucked out because of contractual irregularities. They then won one game out of six in the group stages. In 2010, Braga put them out in the third qualifying round of the Champions League and Utrecht beat them in the Europa League play-off. In 2009, it was another one-win-out-of-six Europa League group campaign.

Celtic are far from being an elite European club these days. How far was obvious when they struggled to beat Shakhter Karagandy in the Champions League play-off stages. Neil Lennon might have painted their 3-2 aggregate win as a victory for the ages but League of Ireland fans can remember St Pat's beating them by the same margin in the Europa League two years ago.

The team from Kazakhstan have gone on to finish bottom of their Europa League group with two points from six games. Elfsborg, who Celtic squeaked past 1-0 in the third qualifying round, won one game out of six in a group topped with a maximum 18 points out of 18 by mighty Red Bull Salzburg who last year got knocked out of the Champions League by FC Dudelange of Luxembourg.

This is the kind of company Celtic will need to get used to in Europe. Meanwhile, their continued dominance of the Scottish Premier League looks like a form of bullying given their vastly superior resources. The club's average home attendance of 46,627 is more than three times than that of the next best supported club Hearts, who get 14,598 at their games. Half of the division's clubs pull in less than 5,500 fans a week.

In other words it's a bit like taking Newcastle United and dumping them into the League of Ireland. They'd win the title by a mile but their fans wouldn't really have that much to be proud of.

When Celtic won nine titles on the trot between 1966 and 1974 their rivals included a Rangers team good enough to win the Cup Winners' Cup in 1972, a Kilmarnock side who made the semi-finals of the 1967 Fairs Cup, a Dunfermline team who made the semis of the 1969 Cup Winners' Cup, Dundee who made the semis of the 1968 Fairs Cup and Hibernian who reached Fairs Cup (1968) and Cup Winners' Cup (1973) quarter-finals.

In those glory days the Lisbon Lions' rising tide lifted all boats. Jock Stein's team won nine in a row because they were a great team, not because there was nothing for them to beat. These times it's different. The Scottish League has never been weaker and without even Rangers to rival them Celtic are being dragged down by the dross beneath them.

Maybe it's time to quit Scottish football altogether. Or maybe the club are happy enough as the team cruises along like a shark devouring every minnow in its path.

The problem is that this shark isn't moving forward anymore. And we all know what happens to a stationary shark.

Irish Independent Sport Star Awards

Pick our magic sports moment of the year and win a trip for two to London. To view the shortlist and cast your vote click here.